Question

Two numbers are such that the ratio between them is 3:5. If each is increased by 10, the ratio between the new numbers so formed is 5:7. Find the original number.

Answer 1

Let the numbers be 3x and 5x.

According to the question we can write as

(3x+10) / (5x+10) = (5/7)

On cross multiplying we get

7(3x+10) = 5(5x+10)

21x+70=25x+50

On rearranging or transposing

70-50=25x-21x

4x=20

x=20/4=5

So the numbers are 15 and 25